amavis problem - lost connection with 127.0.0.1

[Tun]

Hello,

since a few months I'm using zimbra and never had a problem! A week ago I migrated my old server to a new one but unfortunately I have now some problems with Zimbra.

My deferred queue is "full" with emails saying this:

tweety postfix/smtp[15227]: 1C3F95C81D1: to=, relay=127.0.0.1[127.0.0.1]:10024, delay=500, delays=500/0.01/0.01/0, dsn=4.4.2, status=deferred (lost connection with 127.0.0.1[127.0.0.1] while receiving the initial server greeting)

So no emails can get in, and no emails can get out.

Telneting port 10024 (127.0.0.1) -> connection closed by foreign host
Telneting port 10025 (127.0.0.1) -> 554 5.7.1 : Client host rejected: Access denied

But everything is running

Dec 23 14:08:06 tweety zimbramon[15017]: 15017:info: 2008-12-23 14:08:01, STATUS: tweety.xxx.xxx: antispam: Running 
Dec 23 14:08:06 tweety zimbramon[15017]: 15017:info: 2008-12-23 14:08:01, STATUS: tweety.xxx.xxx: antivirus: Running

I use two network cards in this machine, as it's working as a gateway. (192.168.1.2 is connected to the outside, 10.0.0.1 is for the local network)

I already tried to enable @mynetworks in the amavis configuration (/opt/zimbra/conf/amavisd.conf) and changed it to @mynetworks = qw( 127.0.0.0/8 10 10.0.0.0/8 192.168.1.0/16 );
but no success.

Does anyone have an idea what could be the problem?
Thank you very much in advance,
Tun